Comparison of lipid status in the hearts of piglets and rats on short term feeding of marine oils and rapeseed oils

A series of 4 experiments with piglets and one experiment with rats has been conducted to establish the cardiac lipid status of weanling (3 weeks old) male animals fed fats with different contents of docosenoic fatty acids. Experimental fats were rapeseed oil (RSO) (48.0% 22∶1), refined fish oil (RFO) (14.6% 22∶1), partially hydrogenated fish oil (PHFO) (14.3% 22∶1) and lard (0% 22∶1) combined with sunflower seed oil (SFO) in different proportions in diets with 21% total fat. Lipidosis could not be detected in piglets as increased heart weights, by chemical assay for myocardial contents of triglycerides, or by accumulation of docosenoic fatty acids or nonesterified fatty acids (NEFA). In rats, diets with RSO at a level of 16% increased myocardial triglyceride and docosenoic fatty acid contents about 7 times while the effect on cardiac NEFA was inconsistent. Histological examinations of the hearts revealed stainable intracellular fat droplets in some piglets fed 16% RSO for 8 to 13 days, but not after 2,4 and 6 and 16, 19 and 22 days of feeding. After 10 days of feeding, mild to moderate histological lipidosis was found in piglets fed diets containing 2% or more of 22∶1 fatty acids, with no significant difference between RSO, RFO and PHFO in this respect. The same diets in rats gave about 5 times more histological lipidosis than in piglets. This is attributed to a difference in species response, the rat reacting in a more pronounced manner than the piglet. The cardiac lipidosis no-effect level in piglets corresponded to a daily intake of docosenoic fatty acids of 0.4 g per kg body weight. Mild lipidosis was also found in a few animals on docosenoic acid-free diets.     

trans fatty acids. 4. Effects on fatty acid composition of colostrum and milk

trans Isometric fatty acids of partially hydrogenated fish oil (PHFO) consist oftrans 20∶1 andtrans 22∶1 in addition to thetrans isomers of 18∶1, which are abundant in hydrogenated vegetable oils, such as in partially hydrogenated soybean oil (PHSBO). The effects of dietarytrans fatty acids in PHFO and PHSBO on the fatty acid composition of milk were studied at 0 (colostrum) and 21 dayspostpartum in sows. The dietary fats were PHFO (28%trans), or PHSBO (36%trans) and lard. Sunflower seed oil (4%) was added to each diet. The fats were fed from three weeks of age throughout the lactation period of Experiment 1. In Experiment 2 PHFO or “fully” hydrogenated fish oil (HFO) (19%trans), in comparison with coconut oil (CF) (0%trans), was fed with two levels of dietary linoleic acid, 1 and 2.7% from conception throughout the lactation period. Feedingtrans-containing fats led to secretion oftrans fatty acids in the milk lipids. Levels oftrans 18∶1 andtrans 20∶1 in milk lipids, as percentages of totalcis+trans 18∶1 andcis+trans 20∶1, respectively, were about 60% of that of the dietary fats, with no significant differences between PHFO and PHSBO. The levels were similar for colostrum and milk. Feeding HFO gave relatively lesstrans 18∶1 andtrans 20∶1 fatty acids in milk lipids than did PHFO and PHSBO. Only low levels ofcis+trans 22∶1 were found in milk lipids. Feedingtrans-containing fat had no consistent effects on the level of polyenoic fatty acids but reduced the level of saturated fatty acids and increased the level ofcis+trans monoenoic fatty acids. Increasing the dietary level of linoleic acid had no effect on the secretion oftrans fatty acids but increased the level of linoleic acid in milk. The overall conclusion was that the effect of dietary fats containingtrans fatty acids on the fat content and the fatty acid composition of colostrum and milk in sows were moderate to minor.     

Trans fatty acids. 3. Fatty acid composition of the brain and other organs in the newborn piglet

The effects of dietarytrans fatty acids on tissue fatty acid composition were studied in newborn piglets delivered from sows fed partially hydrogenated fish oil (PHFO) (28%trans) or partially hydrogenated soybean oil (PHSBO) (36%trans) in comparison with lard (0%trans) from 3 wk of age and through gestation in Experiment 1, or fed PHFO or “fully” hydrogenated fish oil (HFO) (19%trans) in comparison with coconut oil (CF) (0%trans) with two levels, 1 and 2.7%, of dietary linoleic acid from conception through gestation in Experiment 2. The piglets were sampled immediately after delivery, without having access to mothers' milk. Incorporation oftrans fatty acids into brain PE (phosphatidylethanolamine) were non-detectable or very low (less than 0.1%). The incorporation of 18∶1trans into heart-PE, liver mitochondria-PE, total plasma lipids and adipose tissue was low, and 20∶1trans was not detected. Dietarytrans fatty acids had no consistent effects on the overall fatty acid composition of the different tissue lipids. It is conclude thattrans fatty acids from PHFO, HFO and PHSBO have no significant effects on the fatty acid accretion in the fetal piglet.     

The effect of dietary partially hydrogenated marine oils on desaturation of fatty acids in rat liver microsomes

The influence of dietary partially hydrogenated marine oils on distribution of phospholipid fatty acids in rat liver microsomes was studied with particular reference to the metabolism of linoleic acid. Five groups of weanling rats were fed diets containing 20% (w/w) peanut oil (PO), partially hydrogenated peanut oil (HPO), partially hydrogenated Norwegian capelin oil (HCO), partially hydrogenated herring oil (HHO), and rapeseed oil (RSO) for 10 weeks. The partially hydrogenated oils were supplemented with linoleic acid corresponding to 4.6 cal % in the diets. Accumulation of linoleic acid and reduced amount of total linoleic acid metabolites were observed in liver microsomal phospholipids from rats fed partially hydrogenated oils as compared to PO feeding. The most striking effects on the distribution of ω6-polyunsaturated fatty acids was obtained after feeding HHO, a marine oil with a moderate content oftrans fatty acids in comparison with HPO but rich in isomers of eicosenoic and docosenoic acids. Liver microsomal Δ⁶-as well as Δ⁶-desaturase activities as measured in vitro were reduced in rats kept on HHO as compared to PO dietary treatment. The results obtained suggest that the dietary influence of partially hydrogenated marine oils on the metabolism of linoleic acid might be better related to the intake of isomeric eicosenoic and docosenoic acids than to the total intake oftrans fatty acids.     

Rat testicular lipids and dietary isomeric fatty acids in essential fatty acid deficiency

Weanling rats were fed essential fatty acid-deficient diets, either completely fat-free, or with partially hydrogenated fish oil (PHFO, 28 wt %), or with fractions derived from PHFO containing primarily positional isomers oftrans-eicosenoate (20∶1, 3 wt %) ortrans-docosenoate (22∶1, 3 wt %). Control animals were fed a peanut oil-containing diet (28 wt %). After 5 or 15 weeks on the diet, the content of neutral and phosphorus-containing lipids in the testes was determined. The fatty acid distribution in major lipid classes was analyzed for animals fed the diets for 15 weeks. The testicular stage of maturation or degeneration was assessed by histology. The group fed PHFO exhibited signs of complete testicular degeneration, or lack of maturation, already after 5 weeks, whereas the animals on the diets with the very long chain monoenoic acids suffered severe degenerations only after 15 weeks. In the PHFO-fed rats, a sharp decline in the concentration of testicular triacylglycerols was observed. In all of the essential fatty acid-deficient groups, an increase in testicular sphingomyelin was observed. Cholesterol levels were fairly similar among all dietary groups. The total testicular fatty acids of the PHFO-fed animals contained somewhat more eicosadienoic acid than found in the other groups, and somewhat less (n−9)-acids. In all EFA-deficient groups, (n−6)-acids were lowered, in particular in triacylglycerols and phosphatidyl cholines. The PHFO group did not show a lower (n−6)-concentration than the other deficient groups, in spite of the more severe symptoms of deficiency. There was no evidence of a major accumulation of long chain isomeric fatty acids in the degenerated testes of the PHFO-, 20∶1, and 22∶1-fed groups.     

Cardiac lipids in rats and gerbils fed oils containing C22 fatty acids

Docosenoic acid from rapeseed oil or herring oil in the diet of the young rat promoted an accumulation of cardiac lipid. The triglyceride fraction accounted for most of the deposited fat and contained a high concentration of the docosenoic acid. Liquid rapeseed oil, partially hydrogenated rapeseed oil or partially hydrogenated herring oil increased the amount of cardiac fatty acids at 1 week and led to the development of degenerative lesions at 16 weeks. Whale or seal oils low in C₂₂ fatty acids produced little effect on the amount of lipids in the heart of rats or gerbils. The latter species receiving 20% rapeseed oil in the diet showed a peak in cardiac lipid deposition at 4 days with similar levels of total fatty acids to that of rats, but with a lower concentration of erucic acid. Oil fromLimnanthes douglasii and hydrogenated herring oil also increased the amount of cardiac fatty acids in gerbils. A high intake of docosenoic acid was common to the animals displaying the cardiac alterations. Presented at the AOCS Meeting, Atlantic City, October 1971.     

Studies on monoene fatty acid isomers in hydrogenated fish oils

An analytical study of the geometrical and positional isomerisation of the monoenoic acids of partially hydrogenated fish oil is presented. The results showed that the monoene fatty acids of chain lengths 16, 18, 20 and 22 consisted of 75% in thetrans-form and 25% in thecis-form. The double bonds were distributed symmetrically over the chain length, with well defined maxima in position Δ-9 for the fatty acids of chain length 16 and 18, and in position Δ-11 for the fatty acids of chain length 20 and 22.Trans- andcis-isomers showed the same positional distribution. Geometric as well as positional isomerization seemed to have reached an equilibrium state in the sample investigated. Presented at the ISF-AOCS World Congress, Chicago, October 1970.     

trans fatty acids, 5. Fatty acid composition of lipids of the brain and other organs in suckling piglets

The effects of dietarytrans fatty acids on the fatty acid composition of the brain in comparison with other organs were studied in 3-wk-old suckling piglets. In Experiment (Expt.) 1 the piglets were delivered from sows fed partially hydrogenated fish oil (PHFO) (28%trans), partially hydrogenated soybean oil (PHSBO) (36%trans) or lard (0%trans). In Expt. 2 the piglets were delivered from sows fed PHFO, hydrogenated fish oil (HFO) (19%trans) or coconut fat (CF) (0%trans) with two levels of dietary linoleic acid (1 and 2.7%) according to factorial design. In both experiments the mother's milk was the piglets' only food. The level of incorporation oftrans fatty acids in the organs was dependent on the levels in the diets and independent of fat source (i.e., PHSBO, PHFO or HFO). Incorporation oftrans fatty acids into brain PE (phosphatidylethanolamine) was non-detectable in Expt. 1. In Expt. 2, small amounts (less than 0.5%) of 18∶1trans isomers were found in the brain, the level being slightly more on the lower level of dietary linoleic acid compared to the higher. In the other organs the percentage of 18∶1trans increased in the following order: heart PE, liver mitochondria PE, plasma lipids and subcutaneous adipose tissue. Small amounts of 20∶1trans were found in adipose tissue and plasma lipids. Other very long-chain fatty acids from PHFO or HFO (i.e., 20∶1cis and 22∶1cis+trans) were found in all organ lipids except for brain PE. Dietarytrans fatty acids increased the percentage of 22∶5n−6 in brain PE. Except for the brain and the heart, dietarytrans fatty acids reduced the percentage of saturated fatty acids and increased the percentage of monoenoic acids (includingtrans). The overall conclusion was that dietarytrans fatty acids had no noticeable effect on the brain PE composition but slight to moderate effects on the fatty acid profile of other organs of suckling piglets.     

Effect of the degree of hydrogenation of dietary fish oil on the trans fatty acid content and enzymatic activity of rat hepatic microsomes

The degree of fat hydrogenation and the trans fatty acid content of the diet affect the fatty acid composition of membranes, and the amount and the activity of some membrane enzymes. We describe the effects of four isocaloric diets containing either sunflower oil (SO, 0% trans), fish oil (FO, 0.5% trans), partially hydrogenated fish oil (PHFO, 30% trans), or highly hydrogenated fish oil (HHFO, 3.6% trans) as fat sources on the lipid composition and the trans fatty acid content of rat hepatic microsomes. We also describe the effect of these diets on the cytochrome P-450 content and on the aminopyrine N-demethylase, aniline hydroxylase, and UDP-glucuronyl transferase microsomal activities. Cytochrome P-450 content was dependent on the degree of unsaturation of the diet, being higher for the FO-containing diet and lower for the HHFO diet. Aminopyrine N-demethylase activity also correlated with the degree of unsaturation of the diet as did the cytochrome P-450 content did (FO>SO>PHFO>HHFO). Aniline hydroxylase activity appeared to be independent of the degree of unsaturation of the dietary fat, but correlated with the trans fatty acid content of the diet, which was also reflected in the trans content of the microsomal membranes. UDP-glucuronyl transferase activity was higher for the FO-containing diet than for the SO diet, showing intermediate values after the PHFO and HHFO diets.     

Cardiac fatty acids in rats fed marine oils

Cardiac fatty acids were studied in young rats fed marine oils for 1 week. When the diet contained 0, 0.5, 1, 2, 4, 8 or 16% by weight of partially hydrogenated oil from Norwegian capelin, the concentration of fatty acids in the cardiac tissue was elevated only at the highest level. The amount of the lipid and the content of docosenoic acid in the heart were less than those observed with 15% partially hydrogenated oil from Canadian herring. Nonhydrogenated Peruvian anchovy oil lacking docosenoic acid produced no change in the amount of fat deposited. The extent of fatty acid accumulation in the heart was related to the dietary C₂₂ acids.     

Dietary linoleic acid and the fatty acid profiles in rats fed partially hydrogenated marine oils

The influence of the linoleic acid levels of diets containing partially hydrogenated marine, oils (HMO) rich in isomeric 16∶1, 18∶1, 20∶1 and 22∶1 fatty acids on the fatty acid profiles of lipids from rat liver, heart and adipose tissue was examined. Five groups of rats were fed diets containing 20 wt% fat−16% HMO+4% vegetable oils. In these diets, the linoleic acid contents varied between 1.9% and 14.5% of the dietary fatty acids, whereas the contents oftrans fatty acids were 33% in all groups. A sixth group was fed a partially hydrogenated soybean oil (HSOY) diet containing 8% linoleic acid plus 32%trans fatty acids, mainly 18∶1, and a seventh group, 20% palm oil (PALM), with 10% linoleic acid and notrans fatty acids. As the level of linoleic acid in the HMO diets increased from 1.9% to 8.2%, the contents of (n−6) polyunsaturated fatty acids (PUFA) in the phospholipids increased correspondingly. At this dietary level of linoleic acid, a plateau in (n−6) PUFA was reached that was not affected by further increase in dietary 18∶2(n−6) up to 14.5%. Compared with the HSOY- or PALM-fed rats, the plateau value of 20∶4(n−6) were considerably lower and the contents of 18∶2(n−6) higher in liver phosphatidylcholines (PC) and heart PC. Heart phosphatidylethanolamines (PE) on the contrary, had elevated contents of 20∶4(n−6), but decreased 22∶5(n−6) compared with the PALM group. All groups fed HMO had similar contents oftrans fatty acids, mainly 16∶1 and 18∶1, in their phospholipids, irrespective of the dietary 18∶2 levels, and these contents were lower than in the HSOY group. High levels of linoleic acid consistently found in triglycerides of liver, heart and adipose tissue of rats fed HMO indicated that feeding HMO resulted in a reduction of the conversion of linoleic acid into long chain PUFA that could not be overcome by increasing the dietary level of linoleic acid.     

Influence of partially hydrogenated vegetable and marine oils on lipid metabolism in rat liver and heart

Partially hydrogenated marine oils containing 18∶1-, 20∶1- and 22∶1-isomers and partially hydrogenated peanut oil containing 18∶1-isomers were fed as 24–28 wt % of the diet with or without supplement of linoleic acid. Reference groups were fed peanut, soybean, or rapeseed oils with low or high erucic acid content. Dietary monoene isomers reduced the conversion of linoleic acid into arachidonic acid and the deposition of the latter in liver and heart phosphatidylcholine. This effect was more pronounced for the partially hydrogenated marine oils than for the partially hydrogenated peanut oil. The content oftrans fatty acids in liver phospholipids was similar in groups fed partially hydrogenated fats. The distribution of various phospholipids in heart and liver was unaffected by the dietary fat. The decrease in deposition of arachidonic acid in rats fed partially hydrogenated marine oils was shown in vitro to be a consequence of lower Δ6-desaturase activity rather than an increase in the peroxisomal β-oxidation of arachidonic acid. The lower amounts of arachidonic acid deposited may be a result of competition in the Δ6-desaturation not only from the C22-and C20-monoenoic fatty acids originally present in the partially hydrogenated marine oil, but also from C18- and C16-monoenes produced by peroxisomal β-oxidation of the long-chain fatty acids. Part of this work was presented at the ISF-AOCS Congress, New York City, 1980.     

Incorporation ofcis- andtrans-octadecenoic acids into the membranes of rat liver mitochondria

The incorporation of dietary isomeric fatty acids into the membranes of liver mitochondria was investigated. Three groups of rats were fed diets containing 3% sunflower seed oil plus 15%, 20%, or 25% partially hydrogenated arachis oil. A fourth group was fed 25% partially hydrogenated arachis oil, but no sunflower seed oil. All diets were given for 3, 6, or 10 weeks. After 10 weeks, the content oftrans fatty acids in the lipids of the mitochondrial membranes was 15–19% of the total fatty acids. The composition of thetrans- and thecis-octadecenoic acids in the lipids of the mitochondrial membranes was similar for all groups supplemented with sunflower seed oil (SO), irrespective of time and dietary level of partially hydrogenated arachis oil (HAO). Thecis 18∶1 (n−8), which was a major isomer of the partially hydrogenated arachis oil, was almost excluded from the mitochondrial fatty acids. Likewise, the content oftrans 18∶1 (n−8) was considerably lower in the mitochondrial lipids than in the diet. On the contrary, the content oftrans 18∶1 (n−6) was higher in the mitochondrial lipids than in the diet. In the group fed without sunflower seed oil, isomers of linoleic acid and arachidonic acid were observed in the lipids of mitochondrial membranes. Presented in part at the ISF Congress, Marseille, September 1976.     

Nutritional effects of partially hydrogenated low erucic rapeseed oils

The incidence of cardiac lesions in male rats fed rapeseed oil (Brassica campestris, cultivar ‘Span’) was lower with partially hydrogenated oil (iodine value 78) than with the liquid oil which had been treated in various ways. Another rapeseed oil (Brassica napus, cultivar ‘Tower’) was similarly improved when hydrogenated to iodine value 76.6, but not at iodine value 97.1, as demonstrated in both Sprague-Dawley and Wistar rats. The improved nutritional quality of hydrogenated oil appeared not to be related to the decreased concentration of linolenic acid, because that fatty acid in linseed oil with or without erucic acid did not increase the incidence of lesions. A relatively high concentration of docosahexaenoic acid in the cardiac fatty acids was observed in adversely affected groups, but a lower concentration was found with the appropriately hydrogenated rapeseed oil. Presented in part at the AOCS Meeting, Chicago, September 1976.     

Effects of the degree of unsaturation of coexisting triacylglycerols on cholesterol oxidation

In order to evaluate the effects of the degree of unsaturation of triacylglycerols on cholesterol oxidation, mixtures of purified sardine oil triacylglycerols (iodine value, IV=182.6) and cholesterol; of partially hydrogenated sardine oil triacylglycerols (IV=174.5) and cholesterol; and of fully hydrogenated sardine oil triacylglycerols (IV=92.0) and cholesterol were incubated at 25°C in the dark. The oxidative stability of the samples decreased with increasing degree of unsaturation of the triacylglycerols in the sample mixtures; the induction period for peroxide values (PV) of the sardine oil triacylglycerols and cholesterol was shorter than that of the partially hydrogenated sardine oil triacylglycerols and cholesterol. Certain polyunsaturated fatty acids (PUFAs) in the constituent fatty acids of sardine oil triacylglycerols started to decrease after a shorter induction period compared with that of the partially hydrogenated triacylglycerols. The prominent cholesterol oxides accumulated in the samples were 7β-hydroxycholesterol, 7-ketocholesterol, β-epoxide and cholestane triol. The tendency for accumulation of cholesterol oxides in the time course coincided with the changes in PV as well as the decrease in PUFAs. Cholesterol was oxidized in conjunction with autoxidation of coexisting fish oil triacylglycerols. Although lowering the degree of unsaturation of fish oil triacylglycerols was effective in prolonging the induction period of cholesterol oxidation, the rate of cholesterol oxidation in the cholesterol oxides' formation phase after the induction period was not affected by the difference in the proportion of highly unsaturated fatty acids in the natural and partially hydrogenated triacylglycerols of fish oils.     

Trans fatty acids. 2. Fatty acid composition of the brain and other organs in the mature female pig

Female pigs were fed from three wk of age and up to two years a diet containing partially hydrogenated fish oil (PHFO, 28%trans monoenoic fatty acids), partially hydrogenated soybean oils (PHSBO, 36%trans fatty acids) or lard. No consistent differences were found between PHFO and PHSBO with regard to incorporation oftrans fatty acids in organ lipids, buttrans incorporations were highly organ-specific. Notrans fatty acids were detected in brain phosphatidylethanolamine (PE). The incorporation of monoenoictrans isomers, as a percentage of totalcis + trans, in other organs was highest in subcutaneous adipose tissue and liver mitochondria PE, followed by blood lipids with the lowest level in heart PE. The percentage oftrans isomers compared with that of dietary lipids was consistently lower for 20∶1, compared with 18∶1 in organs from PHFO-fed pigs. The only effect of dietarytrans fatty acids on the fatty acid pattern of brain PE was an increased level of 22∶5n−6. Heart PE and total serum lipids of pigs fed the hydrogenated fats contained higher levels of 18∶2n−6, and these lipids of the PHFO-fed group also contained slightly elevated amounts of 20∶3n−6, 18∶3n−3 and 20∶5n−3. Liver mitochondria PE of the PHFO group also contained higher levels of 20∶3n−6 and 22∶5n−6. Dietarytrans fatty acids caused a consistent decrease of saturated fatty acids compensated by increased levels of monoenes. Thus, it may be concluded that dietary long-chaintrans fatty acids in PHFO behaved similarly metabolically to 18∶1-trans in PHSBO in pigs, without noticeable influence on brain PE composition and with moderate to slight effects on the fatty acid profile of the other organs.     

Monitoring of Fat Content,Free Fatty Acid and Fatty Acid Profile Including <Emphasis Type="Italic">trans</Emphasis> Fat in Pakistani Biscuits

The fat contents of 12 brands of biscuits were extracted and evaluated for free fatty acids (FFA) and their fatty acid composition (FAC). The oil content and FFA varied from 13.7 to 27.6% and 0.2 to 1.0%, respectively. The FAC was analyzed by gas chromatography–mass spectroscopy with particular emphasis on trans fatty acids (TFA). Total saturated, unsaturated, cis-monounsaturated and polyunsaturated fatty acids were determined in the range of 37.9–46.9, 53.0–62.0, 12.3–43.7 and 0.1–9.2%, respectively. The high amount of TFA was observed in all biscuit samples and varied from 9.3 to 34.9%. The quantity and quality of the lipid fraction of the biscuits indicated that the all analyzed biscuits are a rich source of fat, saturated fatty acids and trans fatty acids, consequently not suitable for the health of consumers. The high content of trans fatty acids and palmitic acid also indicated that blends of RBD palm oil and partially hydrogenated oil had been used in the biscuit manufacturing.     

Isovaleroyl triglycerides from the blubber and melon oils of the beluga whale (Delphinapterus leucas)

The fatty acid compositions of the blubber and melon oils from the beluga whale (Delphinapterus leucas) have been determined by gas liquid chromatography (GLC). The melon oil contains a high level (60.1 mole %) of isovaleric acid, substantial amounts of long chain branched acids (16.9%), and very little polyunsaturated material (0.5%). The blubber oil contains less isovaleric (13.2%), fewer long chain branched acids (2.7%), and appreciable amounts (10.9%) of the polyunsaturated acids typical of marine oils. The blubber and melon oils were also examined for lipid class composition by thin layer chromatography on silicic acid, direct GLC of the hydrogenated oil, and gel permeation chromatography. Both oils are composed almost entirely of triglycerides, which can be separated chromatographically into molecules containing 0, 1 and 2 isovaleric acid moieties. No triisovalerin could be detected. The blubber oil contains 68.9 mole % normal triacyl-, 24.2% diacyl-monoisovaleroyl-, and 7.0% monoacyl-diisovaleroyl-triglycerides (acyl=long chain acid). Monoacyl-diisovalerin constitutes 86.7 mole % of the melon oil. This unusual compound may play a role in the echolocation system of the beluga whale.     

Application of methoxy-bromomercuri-adduct fractionation to the analysis of fatty acids of partially hydrogenated marine oils

The fatty acids of a refined and of a partially hydrogenated menhaden oil, iodine value (IV) 84.5, were separated into different classes (e.g., monoene, diene, including pentaene and hexaene) by thin layer chromatography (TLC) of their methoxy-bromomercuri-adducts (MBM). In the solvent system hexane: dioxane, the separation of fatty acids occurred according to the degree of unsaturation. No influence was exerted by either the geometry or the position of the ethylenic bonds. The effect of the various chain lengths (C₁₄−C₂₂) was to broaden the bands, but no overlap occurred among the chain lengths. A wide range of C₂₀ unsaturated fatty acids were prepared by the hydrazine reduction of 20∶5-Δ5,8,11,14,17. These were separated into groups as MBM adducts and identified by comparison of their experimental and calculated equivalent chain lengths (ECL) in gas liquid chromatography (GLC) on SILAR-5CP and SILAR-7CP columns. This confirmed that GLC did not totally separate all groups of isomers of different degrees of unsaturation. The quantitative analysis of both refined and partially hydrogenated (IV-84.5) menhaden oils by GLC was effected by the recovery of the fatty acid methyl esters from the MBM adduct TLC bands with the addition of methyl heptadecanoate (17∶0) as an internal standard, followed by analysis of the different fractions on open-tubular columns coated with SILAR-5CP. For methylene- and nonmethylene-interrupted unsaturated acids, 100% recovery from the MBM adducts was achieved, but in the case of the conjugated dienes the maximal recovery was 70%.     

The deposition of polyunsaturated fatty acids in the rat fed partially hydrogenated vegetable oil

The composition of deposited polyenoic fatty acids in rats fed liquid or partially hydrogenated corn oil was determined by gas chromatography, which did not distinguish isomeric forms, and by lipoxidase which reacted with thecis, cis-methylene-interrupted acids. The two methods gave similar results for the liver fatty acids of rats fed either the unhydrogenated or partially hydrogenated oil. Of the fatty acids from the epididymal fat pads of rats fed the hydrogenated product, an appreciable quantity of linoleate isomers did not react with lipoxidase. The total amount of linoleic acid deposited was related to the total fatty acid pattern of the dietary oil. It appeared that thetrans-acids were mostly metab-olized and that the originalcis,cis-linoleic acid remaining in the partially hydrogenated product was preferentially incorporated into tissues. One of 10 papers to be published from the Symposium “Hydrogenation” presented at the AOCS Meeting, New Orleans, April 1970.